Allelopathic Effects of Conyza canadensis Different Parts on A.fatua and L.multiflorum

[Objective] To study allelopathic effects of C.Canadensis.[Method]Using culture dish method,the allelopathic effects of aqueous extract from different parts of C.canadensis on A.fatua and L.multiflorum were tested.[Result] The results showed that the root,stem,leaf and flower all had negative effect on the seed germination and seedling growth of the two tested weeds.Leaf,stem and flower aqueous extract got higher inhibiting on the seed germination and seedling growth of all tested weeds than the extract of root.At 100 g/L concentration,the inhibition rate of C.canadensis flower,leaf and stem on the germination were all above 84.21%,and above 80% on root,stem length,but the inhibition rate of C.canadensis root were 15.79%-38.46% on the germination and 37.46%-56.75% on the root,stem length.[Conclusion] The leaf,stem and flower were the main parts in allelopathic effects.